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leaking injector seals?


Squrlsquash
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put new injector seals on about a year ago when i swapped from ridiculous trilogy injectors back to stock (as rest of car is stock)

 

started leaking like crazy a few weeks ago, turning the key to try and start and the throttle body under the injectors is wet and whole engine bay smells of fuel. still starts and runs but i prefer my car to not be like my mixtape.

 

any ideas? waiting on another set of seals

thanks

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Clean and dry the area thoroughly. Then use a jumper wire to connect the batt + to the fuel pump test wire next to the aircan. Then watch carefully to see where the leak is. Stock injectors are known to leak around the plastic part.
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okay, will get the car int he garage tomorrow to take a look

been too busy and fed up with quest for the last few months to work on it

 

the test lead for the fuel pump is by the airbox?

anyone have a pic of it?

 

opinion on new vs old injectors?

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Look at your CC actuator. Follow the wiring harness that connects to it back to the passenger fender. It should be hanging right there just in front of the actuator. It might be tucked up under other wiring, but it's there.
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found it was a torn o-ring seal between the top of the injector and the rail.

leak fixed

 

 

ran jumper lead to fuel pump test lead and it seems fuel pressure goes straight out the return

unsure how the fpr is supposed to behave

 

anyone have a test? have a few fpr's and unsure which (if any) work properly

 

 

 

thanks

-Aaron

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That's how the FPR works: by bleeding some of the fuel back to the tank. The fuel pump just tries to shove 50 to 60psi of fuel at the pump's rated flow rate (in gallons per hour, cc's per minute, etc, however you want to measure it). Think of the "injector cover" as a "Y" pipe:

* the bottom of the "Y" is the fuel inlet to the "Y" pipe, fuel comes from the fuel pump.

* one upper branch of the "Y" feeds the two injectors (the same branch feeds BOTH injectors)

* the other upper branch goes into the fuel pressure regulator.

 

The regulator bleeds some of the fuel back to the fuel tank by effectively changing the pipe diameter of it's "Y" branch. Big diameter = lots of fuel flows through the regulator and back to the tank... so the remaining fuel pressure at the other "Y" branch drops a bit. The goal is to make the fuel pressure at the injector inlets exactly 36psi higher than whatever air pressure exists at the spray outlets of the injectors. The injetor tips "see" either atmospheric pressure or turbo boost pressure; they never see intake manifold vacuum since they are above the throttle plates. That little "L" shaped vac hose from the bottom of the fuel pressure regulator monitors the air pressure at the tips of the injectors as an input to the regulator.

 

If the FPR is blocked, or if the hose from the FPR back to the fuel tank is blocked, then the fuel pressure at the injectors will be too high and the engine will run rich, especially at idle, as the injectors will now experience almost the entire 60psi from the fuel pump. If the fuel return hose is partially blocked or restricted (e.g. a dent in the metal line underneath the car) then the FPR will not be able to bleed off enough fuel at low engine fuel loads - e.g. idle - so the fuel pressures at the injectors will be too high. At high engine power settings - where the injectors are flowing a lot of fuel - the fuel pressure regulator doesn't need to bleed off as much fuel volume to control the pressure so, depending on how bad the blockage is, it's possible the actual injector pressure can drop back to the correct 36psi level.

 

Testing the FPR:

* with the engine idling, or with that fuel pump test wire jumpered to the battery + post (so the fuel pump is running), measure the fuel pressure at the "injector cover" - either by inserting a temporary test adapter between the fuel supply hose and the injector cover (as described in the factory service manual) or by removing the allen-head threaded plug at the very top/rear of the injector cover and screwing in a pressure gauge. You should see 36psi at either position. Below 36 psi indicates either a bad FPR, lousy vacuum hose routing (such as the "L" hose being mis-connected to a port below the throttle plate that sees manifold vacuum), injectors that are stuck wide-open, flooding the engine, a dying fuel pump, blocked fuel pick-up in the fuel tank or a fuel pick-up pipe with holes in it causing the pump to suck air out of the tank, a restricted fuel supply hose, or a horribly dirty/plugged fuel filter. Too much pressure indicates a bad FPR or a blocked fuel return hose from the FPR back to the fuel tank. Quick test for that: with the pump not running, disconnect the fuel return hose from the FPR and run a short hose to a plastic gas tank like you'd use for storing lawnmower gas. Re-start the fuel pump. If the pressure is now correct, you've proven your car has a blocked/plugged fuel return line. Pressure still high means the FPR is likely bad or an aftermarket fuel pump was installed that is way too big and is simply overwhelming the FPR.

 

* next test: with the fuel pump still running and the engine either OFF or idling, unplug the "L" shaped vac hose from the bottom of the FPR. The fuel pressure should NOT change when you do this. And if there is gas in that hose, or coming from the bottom port of the FPR where that hose connects, the FPR is shot and MUST be replaced before the car is driven. It's dumping gas into the engine, risking flooding and oil contamination from excessive fuel.

 

mike c.

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